U.S. patent number 6,614,405 [Application Number 09/579,095] was granted by the patent office on 2003-09-02 for frame structure.
This patent grant is currently assigned to Filtronic LK OY. Invention is credited to Kari Lohtander, Esa Mikkonen, Kalevi Pesonen.
United States Patent |
6,614,405 |
Mikkonen , et al. |
September 2, 2003 |
Frame structure
Abstract
The invention relates to frame structures, particularly to
mobile stations and other small-sized portable devices operating at
high frequencies. The frame structure according to the invention is
formed by extrusion, whereby the fixing means required for
fastening components are formed into it during the extrusion. Such
fixing means are preferably pin-like projections which can be
compressed to a rivet fixing the component. Such fixing means can
also be strip-like fixing edges which are bent over the component
edges. With such fixing means it is possible to form at the same
time both a mechanical fixing and a good electrical contact between
the component and the frame structure. During the extrusion it is
also possible to fasten to the frame structure parts made of other
materials, such as fixing means of other types or other components,
such as antennas.
Inventors: |
Mikkonen; Esa (Oulu,
FI), Pesonen; Kalevi (Oulu, FI), Lohtander;
Kari (Oulunsalo, FI) |
Assignee: |
Filtronic LK OY (Kempele,
FI)
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Family
ID: |
8550004 |
Appl.
No.: |
09/579,095 |
Filed: |
May 25, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCTFI9800927 |
Nov 25, 1998 |
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Foreign Application Priority Data
Current U.S.
Class: |
343/872;
343/702 |
Current CPC
Class: |
H01Q
1/1207 (20130101); H01Q 1/243 (20130101); H05K
7/142 (20130101) |
Current International
Class: |
H05K
7/14 (20060101); H01Q 001/42 (); H01Q 001/24 () |
Field of
Search: |
;343/702,7MS,841,846,872
;455/90,128 ;361/829 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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42 15 041 |
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Nov 1992 |
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DE |
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195 29 671 |
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Feb 1996 |
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DE |
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9186473 |
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Nov 1997 |
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DE |
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2 006 535 |
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May 1978 |
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GB |
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Primary Examiner: Wong; Don
Assistant Examiner: Dinh; Trinh Vo
Attorney, Agent or Firm: Darby & Darby
Parent Case Text
This is a continuation of International Application Serial No.
PCT/F198/00927 filed Nov. 25, 1998, the entire disclosure of which
is incorporated herein by reference.
Claims
What is claimed is:
1. A frame for an electronic device, comprising: an extruded frame
structure having a generally planar base with particular dimensions
and upstanding sides extending from the base, said frame structure
supporting substantially all elements of the device; at least one
extruded fixing means for fastening a planar component of the
electronic device to the frame structure by shaping of said fixing
means, the planar dimensions of the component being smaller than
the planar dimensions of the base, said fixing means having been
extruded in one piece with said frame structure during the same
extrusion process that formed the frame structure, and axes of said
fixing means being essentially perpendicular to the base and
extending from the upstanding sides of the frame structure; and
wherein also an electrical contact between the frame structure and
said component is provided by shaping said fixing means.
2. The frame structure according to claim 1, wherein said fixing
means is a clamping edge and said shaping is bending of said
clamping edge.
3. The frame structure according to claim 1, wherein said fixing
means is a projection and said shaping is flattening the end of
said projection.
4. The frame structure according to claim 1, wherein at least one
component is fastened to the frame structure during the
extrusion.
5. The frame structure according to claim 1, further comprising an
antenna radiator having been formed in one piece with the frame
structure.
6. A device comprising: an extruded frame structure having a
generally planar base with particular dimensions and upstanding
sides extending from the base, said frame structure supporting
substantially all elements of the device; at least one extruded
fixing means for fasting a planar component of the device to the
frame structure by shaping of said fixing means, the planar
dimensions of the component being smaller than the planar
dimensions of the base, said fixing means having been extruded in
one piece with said frame structure during the same extrusion
process that formed the frame structure, and axes of said fixing
means being essentially perpendicular to the base and extending
from the upstanding sides of said frame structure, and wherein also
an electrical contact between the frame structure and said
component is provided by shaping said fixing means.
7. The device according to claim 6 comprising second components in
addition to said at least one first component, wherein at least one
second component is between the frame structure and said at least
one first component, and the frame structure and said at least one
first component form a RF shield for at least one second
component.
8. The device according to claim 6, wherein at least one of said at
least one first component is a printed circuit board.
9. The device according to claim 8, wherein said frame structure
comprises at least one partition, which divides a space between the
frame structure and the printed circuit board into at least two
parts, at least one of which is an RF shielded space.
10. The device according to claim 6, wherein at least one first
component is an antenna.
11. The device according to claim 6, wherein the device is a mobile
communication means.
12. The device according to claim 6, said frame structure comprises
a radiator which is formed during the extrusion and which forms an
integral body with the frame structure.
13. A method to manufacture an electronic device, comprising the
steps of, (a) extruding a frame structure of the device and
extruding a fixing means in said frame structure in the same
extrusion step and as one piece, (b) fixing a component to the
frame structure by said fixing means; (c) substantially supporting
all elements of the device on said frame structure; (d)
dimensioning said frame structure whereby the planar dimensions of
said components are smaller than the planar dimensions of said
frame structure; and (e) forming an electrical contact between said
component and the frame structure by shaping said fixing means.
14. The method according to claim 13, wherein said fixing means is
a clamping edge, whereby the method comprises a step in which at
least one component is fixed to the frame structure by bending said
clamping edge.
15. The method according to claim 13, wherein said fixing means is
a projection, whereby the method comprises a step in which at least
one component is fixed to the frame structure by shaping the end of
said projection.
16. The method according to claim 13, wherein said component is
fixed in such a way at least partly in-order to form an RF shield
for components between said component and the frame structure.
17. The method according to claim 13, wherein said component is
fixed in such a way at least partly in order to stiffen the
combined structure.
Description
OBJECT OF THE INVENTION
The object of the invention is a frame structure according to the
preamble of claim 1. The invention relates to frame structures,
particularly to mobile stations and other small-sized portable
equipment operating at high frequencies.
BACKGROUND OF THE INVENTION
Mobile phones utilize frame structures, to which the printed
circuit board of the phone is fixed, whereby the frame structure is
generally manufactured by casting, typically die casting, by deep
drawing, by bending a metal sheet, or from metal coated plastic.
Usually the frame structure comprises partitions which separate the
components or component groups mounted on the device's printed
circuit board from each other, whereby the partitions also form an
RF shield in order to reduce the power of the radio frequency
radiation received or emitted by said component or component group.
Typically the partitions also make the frame more rigid.
The purpose of the frame structure is typically to protect the
internal components of the device and in addition to support the
printed circuit board or boards and other components of the device,
as well as to reduce any interfering radiation generated by device
from spreading into the environment. A purpose of the frame is also
to protect the device's components from external electromechanical
interference sources or signals being coupled to the
components.
Previously there are many known ways to fasten components, such as
printed circuit boards or corresponding, to the frame structure.
Threadings can be made in the frame structure, particularly it its
partitions or in pins made separately in the frame structure, so
that the fastening can be made with screws. As the frame structures
are often made very thin in order to minimize the weight of the
device the partitions must often be equipped with bulges around the
threadings so that there will be sufficiently material around the
threads in order to achieve a firm fastening. One such solution is
presented in the application publication EP-391 020, which presents
a mobile phone frame structure. In the solution presented by the
publication partitions are formed in connection with the frame
structure so that the partitions have thickened places in partition
corners and ends which enable fastening with screw. In a solution
of this kind the components are fixed to the frame with the aid of
screws, which complicates the manufacture of the frame structure
and the assembly of the equipment. First the frame must be cast,
after which the required threadings must be formed in different
places of the structure. In the assembly phase the printed circuit
board must be positioned accurately, so that the fastening holes in
the printed circuit board are accurately registered with the
threadings, and then the screws must be individually screwed. All
this will result in a large number of work steps, which causes
substantial costs in mass production.
The use of screws to fasten printed circuit boards and other
components means that their corresponding threads require extra
space in the frame structure and a corresponding space also on the
printed circuit board which shall be fastened at that place, so
that a component fastened on the printed circuit board will not be
clamped between the printed circuit board and the fixing point.
Thus a screw fastening consumes a substantial area on the printed
circuit board.
In the mass production of mobile stations and corresponding devices
it is essential that there is a minimum number of work steps and
that they can be performed as fast as possible. Further, a
maximally efficient use of the printed circuit board area is of
primary importance in small-sized devices. Such devices must also
be as light as possible, whereby it is an object to manufacture the
components of the device of materials which are as thin and light
as possible, but in spite of this the resulting device must be as
rigid as possible and withstand blows, wear and torsion. Frame
structures have been made for instance of plastics, on the surface
of which a thin metal film is formed in order to obtain electrical
protection characteristics. Plastic is a light material, but a
problem is the low rigidity of plastic structures. In such cases
the rigidity can be increased with the aid of partitions, but then
the size of the device must be increased due to the space required
by such extra reinforcing structures.
Magnesium has also been used as material for frame structures.
Advantages of the magnesium is its lightness, the rigidity of
structures made of it, and a possibility to realize versatile
forms. Disadvantages of the magnesium are on the other hand a low
resistance against corrosion and the high costs, and the threading
bores also cause strength problems. Further a frame made of
magnesium must be coated, which causes an extra work step. The
coating also impairs the electrical characteristics of the
magnesium frame, because the coating causes losses.
SHORT DESCRIPTION OF THE INVENTION
The object of the present invention is to eliminate the above
mentioned disadvantages. An object of the invention is also a
simple, cheap and durable structure. A further object of the
invention is to realize a frame structure which is suitable to be
used in mobile stations and other corresponding devices utilizing
high frequencies, in which the frames must have a robust and rigid
structure which acts as an efficient barrier against
electromagnetic radiation and to which the device's components can
be fixed in a simple, easy and reliable manner.
The objects of the invention are attained by forming the frame
structure by extrusion, and by forming the fixing means required
for fastening the components during the extrusion. Such fixing
means are preferably pin-like projections, which can be compressed
into a rivet fixing the component. Such fixing means can also be
strip-like clamping edges which are bent over the edges of the
component. With the aid of fixing means of this type it is at the
same time possible to form both a mechanical fixing and a good
electrical contact between the component and the frame structure.
During the extrusion it is also possible to fix parts made of other
materials to the frame structure, such as fixing means of different
types and other components, such as antennas.
The frame structure according to the invention is characterized in
what is said in the characterizing clause of the independent claim
concerning the frame structure. The invention also relates to a
device, which is characterized in what is said in the
characterizing clause of the independent claim concerning the
device. Further the invention relates to a method, which is
characterized in what is said in the characterizing clause of the
independent claim concerning the method. The dependent claims
represent other preferred embodiments of the invention.
According to a preferred embodiment of the invention a rivet fixing
can act as the fixing mechanism which replaces the screw fastening.
Then the rivets are extruded in connection with the partitions
belonging to the structure, whereby the rivets are made as
projections directed upwards from the partitions and having a
thickness, which can be the same as that of the partition. In
connection with the fixing of the printed circuit board the free
area of the compartments separated by the partitions is not reduced
due to the fixing means, and the area of the printed circuit board
can be utilized more effectively for components, compared to the
conventional use of screws. A separate work step to enable the
fixing, for instance threading, is avoided because the fixing means
are formed already during the extrusion. The use of rivets
integrated in the frame also facilitates the assembly phase,
because there is no need to mount separate fastening means.
Compressing a rivet is also a rapid step compared to the turning of
a screw. One of the means formed during the extrusion can also be
left so short that it is not thicker than the printed circuit
board, whereby this means acts only as an registering means. The
rivets can at the same time act as contact means on the printed
circuit board, whereby the rivets form an electrical contact
between the frame structure and the component to be fixed. Further,
the rivet fixing can be applied to fix several different materials.
With the aid of the rivet solution according to the invention it is
possible to fasten both hard materials, such as metals, and soft
materials, such as plastics. Riveting is well suited for extruded
materials, because they are readily treated, so that the extrusion
material is almost always a suitable material for rivets.
Preferably the fixing means can be integral with the frame
structure material, whereby the extruded piece is formed from a
single blank. The fixing means can also be a separate part, which
is fixed to the structure during the extrusion. Such a piece fixed
during the extrusion can be for instance a rivet blank or a
threaded pin, which can be used as a fixing means. Also other
required components, such as antennas, connectors or carrying strap
holders and corresponding components can be fixed during the
extrusion.
A separate part fixed during the extrusion can advantageously be
used for instance when a certain location requires material
characteristics which differ from the rest of the frame structure.
The fixed part can differ from the extruded material for instance
regarding wear resistance, conductivity or hardness, whereby two
materials with different characteristics can be reliably combined
when the separate part is fixed to the structure during the
extrusion. The fastening of the separate part will also require no
extra space, because the part is substantially fastened to the
interior of the frame structure wall. The fastening method of the
invention provides a strong joint and a fast fixing.
Another possibility to form a fixing means during the extrusion is
to make strips or clamping edges at the edge of the frame
structure, whereby these strips or edges are bent for instance by
rolling or pressing them in some other way over the edge of the
component to be fixed. Then a rolled edge clamps the fixed
component firmly against the frame's edge. The fixing means can
extend over the whole edge or be shorter than the edge, whereby
there may be one or more such means on the same edge. By making the
fixing means according to the invention on the opposite edges of
the frame a firm fixing is obtained, which at the same time
stiffens the whole structure. When a printed circuit board is
clamped to the frame by rolling the printed circuit board also acts
as a supporting structure for the whole structure. At the same time
it is possible to achieve a good electrical contact between the
frame and the clamped component.
In different embodiments of the invention the above mentioned
fastening methods can be freely combined in the same structure. For
instance, the fixing of a component to be fastened can in the
central part be made by riveting and the edges can be clamped by
rolling. Such a structure forms an extremely rigid, reliable and
advantageous fixing solution for fixing a component.
In addition to fixing printed circuit boards the fixing means
according to the invention can be used to fix also other
components, such as antennas, display and keyboard units,
large-sized separate components and hybrid modules. During
extrusion the extruded material is forced to glide through a tool,
or along the tool, so that it will be formed according to the
extrusion profile of the tool. Extrusion methods are divided in two
classes: direct extrusion and indirect extrusion. In direct
extrusion the product glides in the direction of the pusher. Direct
extrusion is used primarily to produce long profile bars. In
indirect extrusion the product glides against the pusher direction
forming e.g. a body with a bowl shape. For instance aluminum,
copper, brass, zinc, lead and also some steel grades are used as
raw materials. However, the most common and most used material is
aluminum and its alloys. The extrusion can be performed either as
hot extrusion or as cold extrusion, where, however, the blanks are
heated to a soft state before extrusion in order to increase the
shaping characteristics.
The design of different devices can be essentially simplified with
the aid of the frame structure according to the invention, because
with the aid of the extrusion method it is possible to make a wide
diversity of different protecting and fixing means in one
manufacturing step. In one manufacturing step it is possible to
obtain, not only the desired form of the extruded product, but also
the fixing means required to fix the components which shall be
fastened to the structure. At the same time it is possible to form
a structure divided into compartments, whose partitions make the
structure more rigid. At the same time it is possible to make any
required registering pins in the casing structure in order to
facilitate the assembly. All this is achieved by a suitable tool
selection, whereby it is easy to make different forms both rapidly
and reliably only by changing tools. The material can be selected
according to the application. It is for instance possible to make
of aluminum and its alloys different structures which are optimized
regarding corrosion durability. Of metals, for instance the above
mentioned aluminum or aluminum alloys, it is also possible to make
tight structures which act as RF shields.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described below with the aid of some embodiment
examples and with reference to the enclosed figures, in which
FIG. 1 shows an extruded casing structure according to an
embodiment of the invention,
FIG. 2 shows a section of the structure of FIG. 1 in which is
mounted a fixed component,
FIGS. 3A-3F show examples of different rivet models used in the
casing structures according to the invention,
FIGS. 4A-4C show a manner according to a preferred embodiment of
the invention to fix components with the aid of particular clamping
edges,
FIG. 5 shows a manner according to a preferred embodiment of the
invention to fix components with the aid of both clamping edges and
rivets,
FIG. 6 shows a manner according to a preferred embodiment of the
invention to fix an antenna element with the aid of a rivet
fixing,
FIG. 7 shows a manner according to a second preferred embodiment of
the invention to fix an antenna element with the aid of a rivet
fixing,
FIG. 8 shows a manner according to a third preferred embodiment of
the invention to fix an antenna element with the aid of a rivet
fixing,
FIG. 9A-9B shows a manner according to a preferred embodiment of
the invention to fix components during extrusion,
FIG. 10 shows a manner according to a preferred embodiment of the
invention to fix more than one component to a casing structure
according to the invention,
FIG. 11 shows manner according to a preferred embodiment of the
invention to fix more than one component to a casing structure
according to the invention,
FIG. 12 shows a manner according to a preferred embodiment of the
invention to fix more than one component on top of each other with
the aid of rivet fixing,
FIGS. 13A-13E illustrate a manner according to a preferred
embodiment of the invention to fix more than one component on top
of each other,
FIG. 14 shows an antenna and casing structure according to a
preferred embodiment of the invention,
FIG. 15 shows a cross section of the structure in FIG. 14,
FIG. 16 shows a cross section of a casing structure according to a
preferred embodiment of the invention,
FIG. 17 illustrates the embodiment of FIG. 16,
FIG. 18 shows a cross section of a casing structure according to a
preferred embodiment of the invention,
FIG. 19 illustrates the embodiment of FIG. 18, and
FIG. 20 shows a cross section of a casing structure according to a
preferred embodiment of the invention.
The same reference numerals and markings are used for corresponding
parts in the figures.
DESCRIPTION OF SOME PREFERRED EMBODIMENTS OF THE INVENTION
FIG. 1 presents an extruded frame structure according to a
preferred embodiment of the invention, whereby projections 2 and
registering pins 20 are formed in the structure during extrusion
for the fixing of a printed circuit board or some other component
and for creating an electrical connection between the component and
the frame structure. The internal volume of the frame is divided
into sections 4 by the partitions 5. The frame structure also
comprises side walls 3. A cross section along the line A-B is shown
in FIG. 2.
FIG. 2 shows a section of the frame structure according to the
embodiment in FIG. 1, along the line A-B. FIG. 2 shows also a first
component 6, here for instance a printed circuit board, which is
placed in the frame structure 1. The printed circuit board 6 has
holes 2' at points which correspond to the projections 2. In this
embodiment such projections 2 act as rivets, which by compression
can fix the printed circuit board 6 to the frame structure 1 and
form an electrical connection between the frame structure and the
printed circuit board. FIG. 2 also shows a support 20, and such
supports can be used to support the printed circuit board or the
component 6 in the manner shown in FIG. 2. The supports 20 can be
used also as registering pins 20 aiding the registering of the
printed circuit board to the correct fixing position, particularly
when the printed circuit board must be exactly in a desired
position. Then the printed circuit board or component 6 can have a
recess or a hole which accurately corresponds to the form of the
support 20, whereby the support 20 directs the printed circuit
board or component 6 into the correct location and position. The
supports and/or registering pins 20 can be used particularly
advantageously also in such embodiments where no projections 2
registering into the holes 2' are used for the fixing of the
component 6, whereby the projections 2 do not aid in the
positioning of the component into the correct position. In FIG. 2
there are also second components 16 fixed to the printed circuit
board 6 within the RF shielded space 4 between the printed circuit
board and the frame structure. In various embodiments of the
invention, there may be zero, one or more partitions 5, which
divide the space between the printed circuit board or other
component 6 and the frame structure into parts, at least one of
which is an RF shielded space.
FIG. 3 shows examples of different rivet forms which can be
realized with the aid of the projections 2. The top row of FIG. 3
shows a cross section of each rivet form and the bottom row shows
the corresponding rivet form seen from the side of the component 6.
In the rivet form A the rivet is formed by pressing with a concave
tool, whereby the rivet head will become round. The form B is
formed by bending the end of the projection 2 to one side. The form
C again is formed by pressing different parts of the end of the
projection to different sides. Note that the rivet shapes in FIG. 3
are only examples of some rivet forms which can be realized by
extrusion, and the invention is not limited to the use of only
these rivet forms.
The rivet forms of FIG. 3 also illustrate different possible
exemplary forms of the projections 2. A projection can be for
instance a cylinder according to the rivet form A, or a rectangular
prism according to the rivet forms B and C. The invention is not
limited to any particular form of the projection 2, but the
projections 2 can be formed in many different ways according to the
requirements of the embodiment in question.
FIG. 4 shows an example of another preferred embodiment of the
invention. In this embodiment plate-like projections or clamping
edges 7 are used as fixing means, whereby the clamping edges are
bent over the edges of the component to be mounted. FIG. 4
illustrates a series of actions in order to fix the component to
the frame structure. In step 1 there is shown a frame element 1
which has clamping edges 7. The component 6 is placed in the frame
element in the manner shown in step II, and then the clamping edges
7 are bent over the edges of the component 6 in the manner shown in
step III. The clamping edges 7 can be bent over the edges of the
component 6 for instance by rolling or by pressing at one or more
different positions, or in any other known manner. The wall 3 of
the frame has preferably also a step 13, against which the fixed
component is pressed. At the same time the bent edge 7 and/or the
step 13 can form an electrically conducting connection from the
frame 1 to the component 6. In this way the ground plane of the
printed circuit board can be connected to the frame structure 1 in
order to form an RF shield which is as tight as possible. With the
aid of such clamping edges a large-sized component 6, such as a
printed circuit board 6, can also act as a stiffener of the frame
structure 1, which enables the walls of the frame structure to be
made thinner and thus to make an even more lighter device as the
final product.
Advantageously the clamping edges 7 can be as long as the edges of
the fixed component 6, whereby a particularly robust fixing can be
made. However, the clamping edges can also be shorter strips, of
which there may be one or more on different sides of the component
6. The use of shorter strips is advantageous for instance when the
fixed component 6 has an arcuate edge.
FIG. 5 shows a combined structure of the above described fixing
mechanisms according to a preferred embodiment of the invention
which for clamping the printed circuit board 6 utilizes both a
rivet formed by the projection and rolling or bending of the edges
7 over the printed circuit board edges. Then the printed circuit
board is firmly fixed in its middle parts by the rivets 2, and
further the whole structure is reinforced and the edges of the
printed circuit board are supported by the rolled edge 7. The
figure shows as an example only one rivet, but the number of rivets
can be freely selected according the desired fixing points.
FIG. 6 shows another fixing application according to the invention
where more than one component is fixed with fixing means according
to the invention to the same frame structure. In the example of the
embodiment in FIG. 6 rivet fixing is used to fasten the antenna
element 8 to the frame structure 1. The printed circuit board 6 is
fixed to the frame structure 1 either by any of the above presented
means or in some other technique, such as with a screw fastening.
During the extrusion of the frame structure 1 there is formed one
or more projections 2, with which the antenna element 8 is fixed to
the frame 1. FIG. 6 shows as an example the PIFA antenna structure
(Planar Inverted F-antenna), which is intended to be located within
the outer cover of a mobile communication means, whereby the
antenna is not visible to the outside. The antenna comprises a
radiating element 8 and an antenna feed pin 9, which is connected
to the conductor pattern of the printed circuit board 6. In this
solution the ground plane is formed on the printed circuit board 6,
and the antenna element is short circuited to the ground plane
through the frame structure 1.
FIG. 7 shows a method to fasten an antenna element according to a
preferred embodiment of the invention. In this solution the frame
structure acts as the ground plane. The antenna element is fastened
to the cover structure 1 at the opposite side of the cover
structure compared to the printed circuit board 6. The antenna
element is connected to the printed circuit board 6 by the feed pin
9. The frame structure has a hole 9' at the position of the feed
pin.
FIG. 8 shows a method to fasten the antenna element 8 according to
another preferred embodiment of the invention. In this solution the
frame structure acts as the ground plane. At the position of the
antenna the frame structure has a recess or step of a size which is
about the same as that of the antenna and has a depth d which forms
the distance of the antenna element from the ground plane. Due to
the structure according to FIG. 8 the antenna element 8 forms a
very low projection of the cover structure. The antenna element is
connected to the printed circuit board 6 by a feed pin 9. The frame
structure has a hole 9' at the position of the feed pin 9.
According to a preferred embodiment of the invention a separate
piece can be mounted in the frame structure during the extrusion.
FIG. 9 shows an embodiment according to the invention for mounting
a piece 11 in the frame during the extrusion. The extrusion blank
15 has a recess or opening 12 for the separate piece 11, and the
blank and the piece 11 to be fixed to the frame structure are
placed between the extrusion mandrel 13 and the forming pad 14
before the extrusion. This step is in FIG. 9 shown as step I.
During the extrusion the blank 15 is formed so that it encloses a
part of the piece 11 to be fixed to the frame structure, and at the
same time it fixes it firmly to the proper structure in the manner
shown in step II of FIG. 9. The fixed piece can have a gripping
part 11', as in the case of the figure, which is made in a form
which ensures that the piece is firmly held in the extruded
structure. FIG. 9 shows how a pin-like piece, for instance a screw
or any other fastening means is fixed to the frame structure during
extrusion, but the fixed part can also have other forms. One
application is for instance the fixing of an antenna to the frame
of a mobile phone with this method, whereby for instance an antenna
can be directly fixed to the frame according to the FIG. 6, 7 or 8,
and no separate riveting is required.
FIG. 10 shows such a preferred embodiment of the invention where
more than one component 6, 6', 6" on top of each other is fixed to
the frame structure 1. With the method according to the invention
it is possible to fasten for instance the device's printed circuit
board 6, the keyboard or display unit 6' and a seal 6". The
components 6, 6', 6" are preferably fastened in a suitable order,
if the upper components do not have openings for pressing the
fixing projections 2 of the lower components. The partitions 5 or
platforms 5 define the mounting height of the components 6, 6', 6".
The components can also be in more than two layers. For instance in
such an embodiment of the invention where the frame structure
according to the invention is used as a frame structure of a high
frequency device, such as a mobile station, it is advantageous to
add to the structure like that of FIG. 10 for instance a metal
plate as an RF shield between the keyboard unit 6' and the printed
circuit board 6, so that the high frequency signals will not leak
outside the device from the printed circuit board 6 through the
opening of the keyboard unit. With the method according to the
invention it also possible to fasten to the cover structure
components of another type than the planar components, which in
FIG. 10 are exemplified by a large-sized single component or module
6'".
FIG. 11 illustrates such a preferred embodiment of the invention
where fixing with the aid of both projections 2 and clamping edges
7 are utilized in the same device. In this example the bottom
component 6', for instance a printed circuit board 6', is fixed
with the aid of projections 2, and the top component 6, for
instance a metal plate 6, is fixed with the aid of bent or rolled
clamping edges 7'.
FIG. 12 illustrates another method according to the invention to
fix more than one component on top of each other. In the embodiment
of FIG. 12 this is realized with the aid of partitions 5 or narrow
platforms 5' having different heights. The bottom component 6 can
be fixed with the aid of projections 2 formed in the partitions 5.
In this embodiment the top components are fixed with the aid of the
platforms 5'. The bottom component 6 can have an opening for the
platform 5'. The edge of the component 6 can also have a recess for
the platform 5', if the platform 5' is close to the edge of the
component. At the ends of the platforms 5' there are projections 2,
with the aid of which the top component 6' is fixed into its
position.
FIG. 13 illustrates a preferred embodiment of the invention where
the same platform 5' is used for the fixing of more than one
component 6, 6'. In the step 1 of FIG. 13 the platform 5' is shown
before mounting of the components. The platform 5' has one step 13,
13' for each component to be fixed. In step II a first component 6
is placed on the platform 5' on the lower step 13'. In step III the
first component is fixed to the platform 5' by pressing platform
material from the corner 21 over the edges of the fixing hole of
the component 6. In step IV a second component 6' is placed on the
platform 5', and in step V the second component is fixed to the
platform with the aid of a rivet formed by the projection 2.
Further the FIGS. 14 to 20 show some antenna structures which are
suitable to be used in the above presented frame structures. These
antenna structures are integral with the frame structure, and most
preferably they are formed during the manufacturing of the frame
structure, substantially in the same manner as the other details of
the frame structure, as for instance the projections 2. In the
embodiments shown in FIGS. 14 to 20 the material of the frame
structure is most preferably metal, such as aluminum or an aluminum
alloy. In these embodiments the material of the frame structure can
also be a dielectric, such as a plastic, if the frame structure is
coated by an electrically conducting layer, such as a metal layer,
at least over the area of the radiator.
FIG. 14 shows an antenna and frame structure according to a
preferred embodiment of the invention. The figure shows the frame
1, the antenna radiator 8 and the printed circuit board 6, of a
mobile station or another device utilizing high frequency radio
communication. The frame structure 1 and the radiator 8 form a
single integrated component. A ground plane 18 is formed on the
printed circuit board 6 with the aid of an electrically conducting
pattern. The feed line 9 connects the radio frequency signals from
the feeding conductor 19 to the antenna radiator 8. In this
embodiment the feed line 9 can preferably be realized as a
projection of the integral component formed by the radiator and the
frame structure. The feed line can also be realized in other ways,
for instance by a conductor soldered between a separate printed
circuit board and the radiator. The cross section of the structure
along the line A-B is shown in FIG. 15.
FIG. 15 illustrates the structure of the embodiment in FIG. 14,
particularly the cross section of the structure along the line A-B.
The figure shows the device's printed circuit board 6, the feed
line 9 and the antenna radiator 8 and the frame structure 1, which
form an integral body comprising partitions 5 supporting the
printed circuit board 6. In this embodiment the feed line 9 can be
realized as a part of the integral body forming the radiator and
the frame structure.
FIG. 16 illustrates a preferred embodiment of the invention. In
this embodiment the radiator 8 of the antenna structure is in a
different plane than the frame structure 1, slightly outside the
frame structure. A radiator of this type can be formed in the frame
structure 1 for instance after the manufacture by cutting in the
frame structure a slit corresponding to the edges of the radiator,
and bending the radiator outside the frame structure. However, the
invention is not restricted to an embodiment of this type, but the
structure formed by the radiator 8 and the frame structure 1 in
FIG. 16 can also be manufactured in one step, for instance by
casting. The figure also shows the printed circuit board 6 of the
device, the feed line 9 and the partition 5 supporting the printed
circuit board 6.
FIG. 17 is a perspective view illustrating the embodiment of FIG.
16. The figure shows the frame structure 1 and the radiator 8
forming a projection of it. The cross section shown in FIG. 16
represents the line A-B in FIG. 17.
FIG. 18 illustrates a preferred embodiment of the invention. In
this embodiment the radiator 8 is substantially in the same plane
as the side of the frame structure 1. The frame structure 1 has a
recess at the position of the radiator 8. In this embodiment the
ground plane is preferably formed on the printed circuit board 6.
The figure also shows the feed line 9 and a partition 5 supporting
the printed circuit board 6.
FIG. 19 is a perspective view illustrating the embodiment of FIG.
18. The figure shows the frame structure and the radiator 8 forming
a projection of the frame structure. The cross section shown in
FIG. 18 represents the line A-B in FIG. 19.
FIG. 20 shows a cross section of a preferred embodiment of the
invention. In this embodiment the side of the frame structure 1
acts as the ground plane of the antenna structure.
According to the desired material and the manufacturing techniques
the radiator 8 can be bent for instance into the position shown in
FIG. 20. The body formed by the frame structure and the radiator
can also be cast directly into the form shown by FIG. 20. In this
embodiment the frame structure includes a hole 9' for the feed line
9, whereby the feed line can be directed from the printed circuit
board 6 to the radiator 8 through this hole.
The cover structure according to the invention is particularly well
suited for cover structures of mobile stations. The antenna of the
mobile station can be fastened for instance in the ways shown by
FIG. 6, 7, 8 or 9, and the printed circuit boards, the display and
keyboard units can be fixed for instance in the way shown in FIG.
10 or in any other way shown in this application. The antenna
structure formed into the cover structures shown in FIGS. 14 to 20
are particularly well adapted to be realized in connection with
mobile station frame structures.
The rivet fixing is firm, operates reliably and is easily realized.
A rivet is also a durable connection, which does not loosen, which
is possible when for instance using a screw fastening.
Above the invention was described with reference to a few of its
preferred embodiments, but is obvious that the invention can be
modified in many different ways according to the inventive idea
defined by the enclosed claims. For instance, even if the component
to be fastened is preferably flat, it is also possible to fix other
types of components to the cover structure according to the
invention, such as transformers provided with flat fixing legs. The
component can also be of the same material as the frame structure,
for instance in an embodiment where an aluminum plate for the RF
shield is clamped to an aluminum frame structure with the aid of
bendable clamping edges. An excellent mechanical and electrically
tight connection is obtained with this fixing method. Any
extrudable material according to the requirements of the particular
application can be used as the cover structure material. If a
nonconducting material is used as the cover structure material, a
layer of conductive material needs to be applied to the cover
structure in order to form an RF shield according to the invention.
Also, the invention does not limit the use of conventional
fastening methods, such as screw fastening, in the structures
utilizing the invention.
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